Measles Outbreak in the Philippines: Epidemiological and Clinical Characteristics of Hospitalized Children, 2016-2019

Abstract

Background: Measles outbreaks increased worldwide during 2017-19. The largest outbreak in the World Health Organisation Western Pacific region occurred in the Philippines. The aim of this study was to summarise paediatric measles admissions to the national infectious diseases referral hospital in Manila during 2016 to 2019, and consider implications for the Philippines and the wider region. Methods: A retrospective single-centre observational study including 5,562 children aged under five years admitted with measles from January 2016 to December, 2019. We summarised sociodemographic and clinical characteristics, vaccine status, reported exposures and outcomes. Univariable and multivariable logistic regression analyses were undertaken to assess associations between different characteristics of hospitalised children and death. Findings: The median age of children hospitalised with measles was 11 months (interquartile range: 7-28). 84.5% of cases were reported not to have received any measles-containing vaccination (MCV). The case fatality rate was 3.2%, with 30% of deaths occurring among children aged less than 9 months. The following characteristics were associated with increased odds of death: admission during the period of the epidemic (adjusted odds ratio [AOR] 9.40, 95% CI 1.80-49.05), pneumonia (AOR 2.42, 95% CI 1.55-3.78), gastroenteritis (AOR 4.01, 95% CI 2.19-7.35), not receiving vitamin A supplementation (AOR 1.82, 95% CI 1.22-2.72), and not being vaccinated (AOR 2.09, 95% CI 1.07-4.07). Interpretation: No children died who had received two MCVs. MCV1 coverage in the Philippines declined to 72% in 2020. Routine immunization needs to be strengthened and earlier timing of MCV1 requires further evaluation to prevent further outbreaks. Funding Information: This work is in part funded by Nagasaki University (salary support for CS, KA, RN, KA, JS). Declaration of Interests: KM is a member of the WHO Strategic Advisory Group of Experts (SAGE) on Immunization. The other authors declare no conflicting interests Ethics Approval Statement: The study was approved by the SLH research ethics and review unit (Ref: SLH-RERU-2020-010-E Ver 2) and the School of Tropical Medicine and Global Health, Nagasaki University ethical committee (Ref: NU_TMGH_2020-106-0). This was a retrospective analysis of routinely collected anonymised data thus patient or caregiver consent was not required.